The present invention refers to an electric machine incorporating stator and rotor and being of the type which in the stator has axially directed sheet metal laminae for the magnetic flux.
Electric machines of this type are earlier known. One type of those machines is described e.g. in Swedish Pat. No. 7216772-9. In this patent, which protects a method for manufacturing the above mentioned machine, is shown an electric motor in which the stator plates are embedded in plastic material and maintained in their predetermined positions by means of this plastic material. A motor of this type functions very well, but it can on occasion be a non-desirable operation to use a plastic embedding moulding method during the manufacture of motors. The price of the plastic material is, moreover, increasing. The stator embedded in plastic material will also become difficult to cool by means of flowing air.
The drawbacks in the above mentioned electric motors have been set aside by the present invention and an electric machine has been produced which incorporates stator and rotor with a stator built from at least two axial parts and having axially directed sheet metal laminae, the axial edges of which are bent inwards against the centre for forming the rotor cavity and which is mainly characterized in that each stator part at its axial ends is provided with a radially directed plate incorporating axially extending teeth, which are inserted between the edges of the sheet metal laminae for maintaining these spaced apart at a predetermined relative distance.
The axially extending teeth should according to the invention be of plastic material and extend from a plastic layer applied around the radial plate and they should also taper inwards against the sheet metal packet.
The plastic layer around the radial plate can be provided with a groove for attachment of the bearing carrier at the outside of the plate.
It is also suitable that the insulating casing for the stator windings is moulded to the radial plate at the same time as the other plastic moulding.
According to the invention the radial plate should be provided with mounting means, e.g. lugs, whereby it can be attached to an opposite similar plate in another of the axial parts of the stator. All radial plates forming part of the stator can be generally similar, whereby the manufacture of the plates and the stator is appreciable simplified.
As plastic material according to the invention must not be present between the sheet metal laminae it is possible to arrange spaces for circulating air between them.